Harris, the Florida Republican who, as secretary of state, played a central role in the 2000 election recount, said the move is in response to news reports that raised questions about the donations.

The San Diego Union-Tribune reported last week that three former MZM employees claimed they were pressured by MZM founder Mitchell Wade to contribute to the company's political action committee.

"Reading these reports I was very concerned. Nothing has been stated that these contributions were illegal, but I was concerned," said Harris, who's planning to challenge Democratic incumbent Bill Nelson for U.S. Senate next year.

She said she wrote a letter to MZM employees who contributed to her telling them that "if they felt pressured in any way, overtly or tacitly, I wanted to return their donations."

Harris, Cunningham and a number of other politicians, mostly Republicans, received donations from MZM's political action committee or from individual employees.

Harris said she met Wade when he was talking about opening an MZM facility in her district in Sarasota, Fla. At a fund-raiser for her last year, checks from about 20 employees, plus a $10,000 donation from MZM's PAC, brought in about $50,000 for her House re-election campaign, aides said.

MZM officials did not immediately return a message seeking comment yesterday, and Cunningham's spokesman directed questions to his attorney, who did not immediately return a call.